While stats suggested the Philadelphia Eagles needed to overhaul their defense, they only made a few changes. And they are expecting vast improvement.

Safety Malcolm Jenkins, cornerback Nolan Carroll and first-round pick Marcus Smith are the major additions for a defense that was the worst in franchise history in yards allowed. The 6,304 yards the Eagles gave up were 15th-most in NFL history and the 4,636 passing yards were fifth-most.

But the Eagles think they will be much better on that side of the ball. They need the defense to go to the next level to better their results from last year, when they won the NFC East and lost a first-round playoff game to New Orleans.

Jenkins, a former defensive captain on the Saints, gives the secondary a leader it's been missing since Brian Dawkins left after the 2008 season. He signed a three-year, $16.25 million contract on the first day of free agency.

"I've learned the defense really quickly and have been able to transition that on the field," Jenkins said. "I understand why they brought me in and that's to run the secondary and make the calls and I take that seriously so I put in a lot of time learning and studying. Now I'm at the point I sit down and talk to the coaches to see how we can tweak it and go to that advanced course and really start to do some creative things."

Jenkins had 48 tackles, 2.5 sacks, two interceptions and two forced fumbles in 14 games last year, helping the Saints finish second against the pass.

"He's added that true leadership to our back end that we needed," linebacker DeMeco Ryans said. "He's a guy who has stepped in and been vocal, a guy who has stepped in and made plays for us. He's not afraid to make the calls. He steps in. He's done a great job fitting right in with our defense. He's the piece we've been missing. He's really added a lot of experience to our defense, a lot of smarts. We really need him."

Carroll gives the Eagles more depth at cornerback, where Cary Williams and Bradley Fletcher are the incumbent starters and Brandon Boykin is the starter at the nickel spot.

"We understand the depth and we're making each other better," Williams said.

Smith, a linebacker from Louisville, was a surprise selection by the Eagles with the 26th pick in the draft. He's unlikely to start right away in Philadelphia's 3-4 defense, but teammates rave about him.

"He's really stepped in and you really don't see him as a rookie," Ryans said. "He's like one of us already, like a vet already, the way he's stepped in and just meshed with everybody in the locker room."

The team is counting on players to improve because it's their second year under defensive coordinator Billy Davis. After a poor first month last season, the defense came along. While they were allowing yards at record-breaking numbers, they kept teams off the scoreboard. There was a stretch of nine straight games when the defense didn't allow more than 21 points.

Second-year safety Earl Wolff is among many players who feel more comfortable with Davis' system in training camp.

"I feel like I'm out here making calls, running around, flying around," Wolff said. "Last year around this time, I was still trying to figure out what my coverages were. I was still kind of second-guessing myself. Now, I'm real comfortable. Now that I know it like the back of my hand, I can go out and call it and get ready to play."